“…Raman spectroscopy evidenced that Sn 3 O 4 is a very crystalline material with a low amount of defects as can be seen by two sharp, symmetric and strong peaks at 145 and 172 cm À 1 (Fig. 1d), which are the main phonon modes detected in Sn 3 O 4 triclinic structure [10]. As observed in XRD, SnO and SnO 2 vibrational modes were also identified with weak intensity in the Raman spectra, indicated as triangle and star, respectively.…”